One of the main differences between reverbs is whether or not they offer independent left and right signal paths. The ones that do are often referred to as "true stereo" reverbs. Many (most?) do not, instead combining left and right and then spreading the generated reflections across the panorama. Both types, however, are innately stereo effects and as such neither will allow you to completely pan hard left or right without some additional post-processing. This, of course, is meant to emula